Simultaneous analysis of serotonin, melatonin, piceid and resveratrol in fruits using liquid chromatography tandem mass spectrometry

An analytical method was developed for the simultaneous quantification of serotonin, melatonin, trans- and cis-piceid, and trans- and cis-resveratrol using reversed-phase high performance liquid chromatography coupled to mass spectrometry (HPLC-MS) with electrospray ionization (ESI) in both positive and negative ionization modes. HPLC optimal analytical separation was achieved using a mixture of acetonitrile and water with 0.1% formic acid as the mobile phase in linear gradient elution. The mass spectrometry parameters were optimized for reliable quantification and the enhanced selectivity and sensitivity selected reaction monitoring mode (SRM) was applied. For extraction, the direct analysis of initial methanol extracts was compared with further ethyl acetate extraction. In order to demonstrate the applicability of this analytical method, serotonin, melatonin, trans- and cis-piceid, and trans- and cis-resveratrol from 24 kinds of commonly consumed fruits were quantified. The highest serotonin content was found in plantain, while orange bell peppers had the highest melatonin content. Grape samples possessed higher trans- and cis-piceid, and trans- and cis-resveratrol contents than the other fruits. The results indicate that the combination of HPLC-MS detection and simple sample preparation allows the rapid and accurate quantification of serotonin, melatonin, trans- and cis-piceid, and trans- and cis-resveratrol in fruits.     

高效液相色谱法测定果汁和果蔬中柑橘红2号染料

应用高效液相色谱法测定果汁、果蔬中柑橘红2号染料的含量。样品用丙酮-正己烷(1+3)混合溶剂提取,提取液于45℃蒸发至干。用甲酸-乙腈(0.5+99.5)溶液(经正己烷饱和)溶解残渣,正己烷脱脂。以Agilent TC C18色谱柱为分离柱,以乙腈与甲酸(0.1+99.9)溶液按体积比92比8混合作为流动相,用二极管阵列检测器在波长508 nm处进行测定。柑橘红2号染料的质量浓度在0.25~10.0 mg·L-1范围内与其峰面积呈线性关系,测定下限(10S/N)为0.1 mg·kg-1。以果汁、鲜橙和胡萝卜样品为基体,加入3种不同浓度水平的柑橘红2号标准溶液做回收试验,测得回收率在96.3%~104.0%之间,相对标准偏差(n=6)在1.0%~3.6%之间。     

拉曼光谱技术在农产品质量安全检测中的应用

农产品的质量安全与我们老百姓的身体健康和生命安全密不可分。传统的化学检测方法具有需要样品前处理,操作过程复杂以及破坏样品等诸多缺陷。拉曼光谱技术作为一种分析、测试物质分子结构强有力的表征手段,可以快速实现样品的无损伤、定性定量检测分析。随着拉曼光谱技术的不断完善和应用范围的逐渐拓宽,拉曼光谱技术在农产品的质量安全检测中发挥着极其重要作用,并且具有广阔的应用前景。目前,已经有大量的基于拉曼光谱技术检测农产品质量安全的相关研究报道,为了解拉曼光谱技术的检测原理以及发展现状,并跟踪国内外最新研究进展,简述了拉曼光谱技术的基本原理及其发展、拉曼光谱检测装置,深入综述了拉曼光谱技术在果蔬、禽畜、粮食质量安全检测中的最新研究进展,指出了拉曼光谱技术应用在农产品质量安全检测中的现存的技术问题。另外,还简要介绍了国内外部分拉曼光谱仪的部分信息和便携式拉曼光谱仪专利申请状况,展望了该项技术的研究方向和应用前景。     

ICP-AES测定鲜蔬果等农作物中硅

试样经料理机打成浆体,湿-干法（700-750℃）消解完全,HCI-HF溶解后,加入适量H_3BO_3消除氟离子干扰,基体匹配后用ICP-AES测定鲜蔬果等农作物中硅。方法检出限0.48mg/L,回收率88%—120%,ICP-AES测定值与重量法测定值一致。本方法可快速、准确测定Si含量≥2.4mg/kg的农作物样品。     

Ultrasound and its combined application in the improvement of microbial and physicochemical quality of fruits and vegetables: A review

The eating safety and high quality of fruits and vegetables have always been concerned by consumers, so require a safe, non-toxic, environment-friendly technology for their preservation. The application of ultrasound is a potential technology in the preservation of fruits and vegetables. This paper describes the ultrasound mechanism for inactivating microorganisms, with the cavitation phenomena of ultrasound being considered as a main effect. Effect of ultrasound on microorganisms of fruits and vegetables was discussed. Ultrasound alone and its combined treatments can be an effective method to inactivate the spoilage and pathogenic microorganisms on the surface of fruit and vegetables. Effect of ultrasound on physicochemical quality of fruits and vegetables was reviewed. Ultrasound and its combined treatments reduced mass loss, decreased color change, maintained firmness, enhanced and inhibited enzyme activity as well as preserving nutritional components such as total phenolic, total flavonoids, anthocyanin, and ascorbic acid.     

液相色谱-串联质谱法测定果蔬中双三氟虫脲、四氯虫酰胺和氰虫酰胺残留

建立了蔬菜和水果中双三氟虫脲、四氯虫酰胺和氰虫酰胺3种新型杀虫剂的分散固相萃取-液相色谱-串联质谱检测方法.样品经乙腈均质提取,混合使用乙二胺-N-丙基硅烷(PSA)和C18基质分散净化剂进行净化,液相色谱-三重四极杆串联质谱(LC-MS/MS)同时进行检测.双三氟虫脲和四氯虫酰胺采用多反应监测负离子模式,氰虫酰胺采用多反应监测正离子模式.双三氟虫脲在苹果、洋葱和经微波处理的洋葱样品中均不存在基质效应,可采用纯溶剂标准外标法或者采用基质匹配标准溶液定量检测; 四氯虫酰胺和氰虫酰胺存在程度不同的基质减弱效应,采用空白基质匹配的校正标准曲线外标法定量.3种杀虫剂均在0.2～100 μg/L线性范围内具有良好的线性关系,相关系数均大于0.9990.在0.005～2.000 mg/kg范围内,平均添加回收率为81.6％～99.9％,相对标准偏差为3.6％～9.8％.氰虫酰胺、四氯虫酰胺和双三氟虫脲的检出限分别为0.064,0.048和0.001 μg/kg,定量限分别为0.210, 0.160和0.004 μg/kg.     

Flavonoids in Selected Mediterranean Fruits: Extraction,Electrochemical Detection and Total Antioxidant Capacity Evaluation

Flavonoids are natural phenolic derivatives that, in low concentration, can provide health benefits by preventing biomolecules (proteins, nucleic acids, lipids, sugars) oxidative damage through free radical mediated reactions. The flavonoids, in selected Mediterranean seasonal fruits: apricot, sour cherry, plum, pomegranate, date, prickly pear (cactus fruit), and nectarine, by RP‐HPLC, coupled with photodiode array and electrochemical detectors, after microwave‐ultrasound assisted extraction, using flavonoid standards, were detected. The total antioxidant capacity in the lyophilized fruit extracts, by differential pulse voltammetry, (electrochemical index‐EI), integrated peak area, and chronoamperometry, was evaluated. In the lyophilized fruit extracts, and the catechin standard, the free radical scavenger efficient concentration (EC₅₀), using DPPH^. assay, was determined.     

Multiresidue pesticide analysis of fruits by ultra-performance liquid chromatography tandem mass spectrometry

Ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC–MS–MS) has been used for screening and quantification of 32 pesticides and metabolites in two fruit matrices. The compounds investigated belonged to different chemical families of insecticides, acaricides, fungicides, and herbicides; several metabolites were also included. Quantification was conducted using matrix-matched standards calibration; response was a linear function of concentration in the range tested (10–500 ng mL⁻¹). The method was validated with blank samples of lemon and raisin spiked at 0.01 and 0.1 mg kg⁻¹, and recoveries were satisfactory, between 70 and 110%, for most of the pesticides tested and relative standard deviations were below 15% (n = 5 at each spiking level). Excellent sensitivity resulted in limits of detection for all compounds well below 0.01 mg kg⁻¹, with the limit of quantification being validated at 0.01 mg kg⁻¹. The UPLC system generates narrow peaks (approx. 5 s), thus increasing peak height and improving sensitivity. This improved separation efficiency facilitates adequate resolution not only of the analytes but also of matrix interferences compared with conventional HPLC. The method developed could also resolve some geometric isomers. The main advantage of this approach is the high sample throughput achieved because of the short analysis time, which enables satisfactory separation of all the compounds in less than 5 min per sample.     

Development and validation of a multi-residue method for the determination of pesticides in processed fruits and vegetables using liquid chromatography–electrospray ionization tandem mass spectrometry

A sensitive multi-residue analytical method, utilizing ethyl acetate extraction and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS), has been developed and validated for simultaneous determination of 28 pesticides of different chemical classes (polar organophosphates, carbamates, strobilurines, neonicotinoids, amides, pyrimidines, benzimidazoles, imidazoles and triazoles), and their transformation products, in processed fruit and vegetables. Two precursor-product ion transitions were monitored for each pesticide in selected reaction monitoring (SRM) mode. Linearity (r (2) > or = 0.99) was good over the concentration range 0.5 to 100 microg L(-1) for all the pesticides, and instrumental detection limits ranged from 0.1 to 1 microg L(-1). Mean recovery for fruit and vegetables spiked at 0.010 mg kg(-1) ranged from 65 to 94.4%, and relative standard deviations ranged from 9.0 to 20.0%. When the amount spiked was 0.050 mg kg(-1) recoveries ranged from 72.5 to 90% and relative standard deviations were from 6.1 to 19.0%. Method detection limits were from 0.002 to 0.007 mg kg(-1) for the different food matrices studied. The method was used to monitor pesticide residues in a wide variety of fruits and vegetables.     

Application of matrix solid-phase dispersion and liquid chromatography–mass spectrometry to fungicide residue analysis in fruits and vegetables

A method based on matrix solid-phase dispersion (MSPD) and liquid chromatography-electrospay ionization-mass spectrometry used to analyze fifteen fungicide residues in fruits and vegetables is described. The method required only 0.5 g of sample, C(18)-bonded silica was used as dispersant sorbent, and ethyl acetate was used as eluting solvent. Fortified recoveries in apple, orange, banana, lettuce, grape and tomato samples ranged from 71% to 102% and relative standard deviations were less than 13% with fortified levels of 0.03-1.5 mg kg(-1). Detection and quantification limits were 1 approximately 30 microg kg(-1) and 4 approximately 100 microg kg(-1), respectively, with linear calibration curves extending up to 15 mg kg(-1). The analytical characteristics of MSPD compared very favorably with those found for a classical multiresidue method: the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. The method was applied to determine the fungicides in real samples. Liquid chromatography-tandem mass spectrometry (LC-MS-MS) was used as confirmatory tool for positive samples.